Single finger-opening collapsible safety closure caps are generally useful for arthritic sufferers needing quick and easy access into medication receptacles and the like. Most of these previously known closures include a finger depressible region for allowing a finger to press the closure, permitting its removal from a container or receptacle. For example, U.S. Pat. Nos. 3,934,745 to Lovell; 4,187,953 to Turner; 4,220,262 to Uhlig et al; and 4,500,006 to Lafortune et al all disclose single finger opening collapsible closures for containers including finger depressible regions to convert the downward force executed by the finger into a disengagement force to remove the closure from the container. However, while these closures facilitate easy single finger removeability, they are not "childproof", and therefore they allow children unauthorized access to a container's contents.
Rubber and other elastic bottle stoppers or plugs have been long known. The U.S. Pat. No. 3,578,193 to Steiner shows such an elastic stopper in the form of a single finger opening closure equipped with a finger receiving well, the closure being removed from a container when finger pressure is applied within the well. Also see Bramming U.S. Pat. No. 2,746,632. Unfortunately, due to the closure's elasticity, changes in ambient temperatures may cause the premature opening of a container utilizing these types of closures. Additionally, elastic closures per se, typically used in conjunction with laboratory test tubes and the like, are relatively expensive to mass produce because of compounding requirements and the necessity of using relatively large quantities of material. Other disadvantages of elastic stoppers when employed in the pharmaceutical packaging industry include the fact that they are usually formed of compounded materials, components of which may cause contamination, or eventual degradation.
The U.S. Pat. No. 4,413,748 to Kessler et al discloses a double finger-collapsible closure equipped with a pair of spaced, D-shaped, finger receiving wells for permitting the removal thereof upon finger pinching motion executed within the wells. This cap is preferably formed as a one-piece molded structure, utilizing a resilient thermoplastic material, such as polyethylene or polypropylene, which does not readily deform or dis-shape when exposed to increased ambient temperatures. Furthermore, this cap is childproof as a child's attempt to deform or rotate a closure of this type would be very difficult, deterring further attempts of unauthorized access. However, this construction, because of having two finger wells, is often not suitable for smaller containers such as bottles.
Containers for keeping potentially dangerous solid materials, such as medicines, must be provided with closures which are easy to install and remove, and which will securely retain the solid materials within their containers. Closures must be operable with sufficient ease to assure that container contents are not inadvertently spilled or otherwise discharged during closure installation or removal.
It is desirable that closures for dangerous material containers be "childproof" in the sense that at least two distinct types of movements must be performed in proper sequence to effect closure removal. Furthermore, it is desirable that such closures have relatively simple configurations which can be molded easily from relatively inexpensive plastic materials. Additionally, it is desirable that such closures be characterized by smooth lines which provide an aesthetically pleasing appearance. Additionally in some instances there is a need to provide closures which will prevent pressure buildups by venting gases from within a container.
Except for Kessler U.S. Pat. No. 4,413,748, previously proposed container closure caps have not adequately addressed the foregoing needs. Many are either undesirably difficult to operate, or they close insecurely. Many are of unduly complex configuration, have unattractive appearances, and/or are undesirably expensive to mold from plastic materials. Most fail to address the need for a gas venting capability.
No single finger-opening resilient cap has previously been available which will not readily deform or dis-shape due to increased ambient temperatures, which will further prevent an unauthorized child's access, and will provide an easy removable closure for adults, especially adults afflicted with arthritis. Furthermore, there is a need for a closure or cap of this type, especially when utilized in conjunction with pill containers and which will eliminate the need for cotton fillers usually provided to maintain solid medicines stationary within their containers.